I am more into analysing the alien breeding program.
It seems to have started with the Boas abduction in the 50's where Boas was made to have sex with what appeared to be a deformed woman.
Then by the time of the Barney and Betty Hill abduction they began taking eggs and sperm. The proliferation of sperm banks and in vitro fertilization provided an unlimited supply of genetic material which could be clandestinely taken for alien breeding purposes.
But the problem was the time factor. I think they wanted the fake alien invasion by 1980 and supposing Boas had descendents (they gave him a nice place in California I believe) they would not be of breeding age until the 1960s and their descendents in 1980. Geometrically it just did not add up. But cows are born and grow to full size in what a couple of years?
The other method to increase the number of aliens is to have articifical wombs. That way even if its normal human growth time you could have an alien army in 16 to 18 years. That would probably be the Dulce program.